Hydrogen transfer reactions including hydrogenation reactions and dehydrogenation reactions are widely used to synthesize low-molecular and polymeric organic compounds.
However, a catalytic hydrogenation reaction in which hydrogenation (hydrogen reduction) is performed using molecular hydrogen in the presence of a homogeneous catalyst is highly substrate-dependent; thus, significant changes in the central metal or the ligand of the catalyst, the reaction conditions, and the like, according to the type of substrate have been necessary. In particular, hydrogenation reactions with substrates containing ester, amide, carbamate, urea, carboxylic acid, carboxylic acid anhydride, or the like are generally considered difficult because they have a carbonyl group stable (inactive) in the hydrogenation reaction.
A recent report discloses that a ruthenium complex in which two bidentate ligands having a nitrogen atom (N) and a phosphorus atom (P) in the molecule are coordinated with ruthenium (Ru) serves as an effective catalyst for hydrogenation reaction with stable carbonyl groups, such as amide, carbamate, urea, carboxylic acid, or the like (Patent Document 1). However, there has been a demand for a catalyst capable of advancing hydrogen transfer reactions, such as a hydrogenation reaction, of various substrates having a stable carbonyl group with a high yield under milder conditions.